Not surprisingly, you use present tense for actions that are currently happening. But (surprise!) you may also use present tense for some actions that happened a long time ago and for some actions that never happened at all. The historical present is a way to write about history or literature:
On December 7, 1941, President Franklin Delano Roosevelt tells the nation about the attack on Pearl Harbor. The nation immediately declares war.In the first sentence, tells and declares are in present tense, even though the sentence concerns events that occurred decades ago. Here the historical present makes the history more dramatic. (Non-historians often tell a story in present tense also, just to make the account more vivid.) In the second sentence, faces and represents are in present tense.Harry Potter faces three tests when he represents Hogwarts in the tournament.
The idea is that for each reader who opens the book, the story begins anew. With the logic that you have come to know and love in English grammar, the events are always happening, even though Harry Potter is a fictional character and the events never happened.
